Birds of the Peloncillo Region: Globally Significant
Biologically & Recreationally Birds represent one of the most visible aspects of biodiversity in any ecosystem. Though some depend on concealment from predators, birds’ extreme mobility frees many to be showy, noisy and colorful. Birds’ conspicuousness has sparked a huge, multi-million-dollar recreation industry. By some estimates more than 24 million Americans regularly travel to watch birds.
Outstanding Features:
North American birds found in any given area can be divided into several categories–migrants, vagrants, winter residents, summer breeding residents––each with different needs and varying dependence on the local area. Because of its prime geographic location between wintering and summering grounds of hundreds of bird species, the Peloncillo region boasts a list of over 50 migrant species that routinely pass through here but do not linger. As a major migratory pathway, this region helps sustain the bird diversity of the rest of the U.S. and Mexico–not to menti on Canada and the New World tropics.
Many additional long-distance travelers spend some length of time in the Peloncillo region. The region’s relatively mild and productive winters support suites of sparrows, hawks, and waterfowl. Wintering species here may also include sandhill cranes hatched the summer before in the marshes of northeastern Siberia. Summer birds here include Swainson’s hawks that spend our winter months on the pampas of Argentina, and sulphur-bellied flycatchers from Amazonia. Another 90 species are periodic visitors or vagrants seen by the watchful and lucky, including many tropical and subtropical species that reach no farther north than this. These, plus some unique Sky Island endemics, are largely responsible for making Southeastern Arizona and Southwestern New Mexico one of the world’s most popular birding hotspots. Still other “rare” species are irruptive in nature, occurring only when environmental conditions require them to wander in search of suitable habitat.
Perhaps most important to the birds themselves, however, is the role this area plays as full-time or summer range for approximately 150 species known or thought to breed here. Many species known to breed in surrounding mountain ranges or valleys have yet to be recorded nesting in the Peloncillo region, but such documentation is improving. In quadrat-by-quadrat sampling of breeding bird diversity across Arizona, the Peloncillo region revealed one of the five richest assemblages in the state, with 87 species of breeding bird recorded in just one ten-square -mile block.
In terms of conservation, resident species and migratory species have different needs and are worth considering somewhat separately. In the Peloncillo region, the resident birds remain close to home their entire lives and are completely dependent on local environmental conditions. A fire, prolonged drought, or a change in management practices can drastically affect local resident populations. Migrants, on the other hand, are especially vulnerable to fragmentation of flyways and to the degradation of a relatively small number of key refueling spots (some of which are well known, while others remain known only to the birds themselves). While rare migrating vagrants tend to attract the most attention from birders, the greatest conservation value of the Peloncillo region is as home to this tremendous suite of resident breeders, for whom the habitats here provide a lifetime of sustenance.
As a testament to the region’s diversity and conservation value, various parts of the Peloncillo region have received attention under the National Audubon Society “important bird areas” (IBA) program. Sites are chosen by each state chapter, on the basis of presence of state or federally listed endangered and threatened species; Partners in Flight2 priority species (PIF); rare, unique, or representative habitats; significant concentrations of shorebirds, raptors, or particular other species or assemblages; and value to long-term research and/or monitoring. New Mexico lists the Animas Mountains as a whole, the Animas Valley’s ciénegas , and the Peloncillo Mountains’ Clanton Canyon as IBA’s. The Animas are described as follows: This spur of the Sierra Madre is the best example of "Mexican" mountains in New Mexico. This area is the only place in the state where Mexican Chickadee and Yellow-eyed Junco breed. In also contains other "southwestern NM" PIF species including Red-faced Warbler, Greater Pewee, Gould's Wild Turkey, Painted Redstart, and Olive Warbler. The valleys around the mountains will contain Mexican Jay, Verdin, Crissal Thrasher, Bendire's Thrasher, Cactus Wren, Lesser Nighthawk, Cassin's Sparrow, and Botteri's Sparrow.
Montezuma Quail
The southern Animas Valley ciénegas are highlighted for “…contain[ing] the largest Botteri's Sparrow population in New Mexico… [and] breeding Arizona Grasshopper Sparrows. In migration and winter other priority grassland species include Sprague's Pipit and Baird's Sparrow.” Clanton Canyon is highlighted for its “state threatened species, species in rare/unique habitat, [including year-round residents] Montezuma Quail, Whiskered Screech Owl, Western Screech Owl, Northern Pygmy Owl, Arizona Woodpecker, Acorn Woodpecker, Juniper and Bridled Titmouse, Bushtit, Hutton's Vireo, Spotted Towhee, and Canyon Towhee.... Summer residents include Band-tailed Pigeon, Poorwill, Whip-poor-will, Elf Owl, Dusky-capped Flycatcher, Phainopepla, Grace's Warbler, Black-throated Gray Warbler, Hepatic Tanager, and Scott's Oriole. Yellow-eyed Junco and Mexican Chickadee are present primarily in winter.” Arizona has yet to confirm many of its proposed IBA’s, but Peloncillo-area nominees include Guadalupe Canyon and the San Bernardino NWR.
A by-product of the bird watching industry is contributory information on bird populations and movements on a regular basis—in the form of daily, monthly and annual reports. Audubon Christmas Bird Count information, Breeding Bird Surveys, checklists and rare bird sighting information have all provided important information concerning avian distribution and abundance. The challenge is that most of this information may be termed natural history but not science, because it is neither peer-reviewed nor subject to uniform standards. Nearly all of the information comes from voluntary services of bird- watchers. However, it is useful information and comprises a large amount of the knowledge of the birds of the Peloncillo region.
Geographic Scope. Species lists from birdwatchers and bird surveys from the greater Peloncillo region, including the Chiricahua Mountains, inform much of this discussion. Excellent bird lists and surveys have been compiled for The Bioresearch Ranch in the central Peloncillo Mountains, the Gray Ranch, Guadalupe Canyon, and Cajon Bonito in Mexico.
Discussion of Species by Habitat Communities
The Peloncillo Mountains, situated between the Chihuahuan and Sonoran Deserts and with the influence of both the Rocky Mountains and the Sierra Madre, are ideally located for biodiversity. The Sky Island mountain ranges of southeastern Arizona, southwestern New Mexico, and northern Sonora have long been recognized as centers of biodiversity. The Peloncillos represent the most contiguous link between the rich habitats of the Sierra Madre in central Mexico and the western U.S.
Within the study area, a variety of habitats from grassland and playa lakes to desert riparian, oak woodland, and pine forest each support distinct avifauna. With the inclusion of the higher elevations found in the Animas Range and the unique wet canyons of Cajon Bonito in Mexico, the bird list reaches 362 species. Of the 28 species of birds occurring in New Mexico listed as threatened or endangered under US or state law, 23 are found in the Peloncillo study area.
Playa Communities
The low elevation playa habitats are most important as wintering grounds for northern migrants. Large flocks of sandhill cranes and smaller groups of shorebirds such as killdeer and snipe utilize the shallow playa lakes around Lordsburg, New Mexico, as roosting and feeding areas. These shallow lakes also provide roosting and summer nesting habitat for a variety of shorebirds, including killdeer and smaller numbers of American avocets and black-necked stilts.
Desert and Grassland Communities
Lower elevation grassland habitats are also important wintering grounds for northern migrants, but are perhaps even more valuable to breeding species such as Swainson’s hawks, meadowlarks, and grassland sparrows. Twenty-one species of sparrows are either winter residents or permanent residents of the grassland communities within the Peloncillo region. These include the Arizona race of the grasshopper sparrow (Ammodramus savannarum ammolegus), a race found only in extreme southeast Arizona and southwest New Mexico. This subspecies is listed as threatened by the state of New Mexico. Along with grasshopper sparrows, Botteri’s sparrows are perhaps the area’s most prestigious sparrow residents. The Botteri’s sparrow is known to breed in just a handful of New Mexico locales, with the Animas Valley’s sacaton grasslands being the most important. Baird’s sparrows regularly migrate through here, but can stay for winter when seed crops are good.
Within New Mexico, the Arizona grasshopper sparrow is known to breed only on the Gray Ranch in the southern Animas and the western Playas valleys. This limited range can be attributed in part to the West-wide decline in open native grasslands. Although the species also expands into nearby weed patches and even agricultural areas (e.g. alfalfa fields) during migration and winter, it as entirely dependent on areas of relatively lush native grassland during the breeding season. NMGFD studies initiated in 1987 have shown wide year-to-year fluctuations in breeding numbers, with populations rising and dropping by as much as 64% in a two year period. These fluctuations can be alarming in a bird with such limited range and such strong dependence on a vanishing habitat. However, long-term studies suggest that these cyclical declines and resurgences may be a feature of this bird’s natural population dynamics.4 Efforts to maintain the region’s open grasslands will certainly help this species survive such fluctuations.
The southwestern subspecies of eastern meadowlark (Sturnella magna lilianae) found here is so distinctive that some authorities have proposed splitting it off into a separate species, the Lilians’s or southwestern meadowlark, giving the area another unique form. Grasslands in the Animas Valley harbor especially large numbers of wintering Chestnut- collared Longspurs, along with regular migrant and occasional wintering individuals of the related McCown’s longspur.
Desert scrub habitat is home to Gambel’s quail, greater roadrunners, black-throated sparrows, and many other species. Lark sparrows and Crissal thrashers nest in these shrub lands, while Bendire’s thrashers select areas intermediate between grassland and shrub land for breeding.
The reestablishment of prairie dogs on portions of the Gray Ranch has provided short - grass habitat critical to imperiled mountain plovers5 and long-billed curlews. Prairie dog towns and grazed pastures also provide winter habitat for ferruginous hawks, golden eagles and burrowing owls.
Low- and Mid-Elevation Riparian Systems
Southwestern riparian systems are among the most endangered and critical habitats in North America. These oases provide food, water, and shelter for a variety of migrants and residents alike, both mammalian and avian. Very little permanent water is found in the Peloncillo region, so the few springs, perennial streams, and even stock tanks scattered throughout the area are critical to the diversity of species found in the mountains. Low elevation riparian strands of Fremont cottonwood and Goodding willow and the higher elevation Arizona sycamore riparian forest support some of the rarest birds found in the United States. Guadalupe Canyon on the U.S. Mexico border is a well-known location for Mexican species that only rarely cross the border into the U.S. The first U.S. record for fan-tailed warbler ( Euthlypis lachrymosa) was a bird collected in here in 1961, and another was seen September 5–8, 1990. Guadalupe Canyon is also habitat for other rare species, including buff-collared nightjar, Lucifer hummingbird, thick-billed kingbird, tropical kingbird and yellow-green vireo.
The lush, watered canyons of Cajon Bonito just south of the U.S.-Mexico border provide the best riparian habitat found within the region and contribute several species to the overall bird list. Cajon Bonito is the site for three records of American dippers—the only Sonoran records for this bird known to frequent only tumbling mountain streams. Many of the same rare species found in Guadalupe Canyon are found here (thick-billed and tropical kingbird, buff-collared nightjar, Lucifer hummingbird) as well as at least one species, white-tipped dove, not recorded for Arizona. Both rufous-capped and fan-tailed warblers have been recorded at Cajon Bonito as has rose-throated becard and green kingfisher. The canyon also provides nesting habitat for both gray hawk and common black-hawk and may provide wintering habitat for elegant trogons, which nest in the nearby Chiricahua Mountains. A noteworthy hummingbird species recorded at Cajon Bonito is the plain-capped starthroat, a Mexican species found only rarely in the U.S. The rarest species seen at Cajon Bonito is an adult white wagtail (Motocilla alba ) seen April 30, 1974.6 This is a bird of the high Arctic with only a few enigmatic sightings south of Alaska, including this one.
Mixed Oak Woodlands and Grasslands
These middle elevations are widely represented in the Peloncillo Mountains and include habitats important to Montezuma quail, violet-crowned and Lucifer hummingbirds, western scrub and pinyon jays, and acorn woodpeckers. This habitat may also be an important migratory pathway along the mountain flanks for woodland species such as the black-throated gray warbler migrating between the tropics and western U.S. The Gould’s wild turkey (Meleagris gallopavo mexicana) found here is a race of wild turkey historically found in most of the Sky Island mountain ranges. This turkey was extirpated from its entire US range except for the Peloncillo Mountains. It has since been reintroduced into other ranges (with mixed success), and has recolonized at least one additional range on its own.
Coniferous Forests and Mountain Meadows
The highest elevations in the Peloncillo region occur in the Animas Mountains and Sierra San Luis at more than 8,500 feet. These mountains contain most of the high-elevation coniferous forest in the region and best populations of higher-elevation birds such as yellow-eyed junco, greater pewee, red-faced warbler and eared quetzal. The eared quetzal, formerly called eared trogon, is a mysterious bird not well known even in its stronghold of the Sierra Madre. It has occurred sporadically in the Sky Islands of Arizona with apparent irruption years of 1977 and 1991 when multiple birds appeared in the Chiricahua and Huachuca Mountains of southeastern Arizona. There are unconfirmed reports of eared quetzal from the Animas Mountains, although the bird is not officially recorded for New Mexico. The high elevations of the Animas, an area rarely visited by birders, provides ideal habitat for the species and is closer to the core area of their habitat, the coniferous forests of the Sierra Madre in Chihuahua, than any of the Arizona locations. The eared quetzal is a mountain trogon, adapted to high pine forests and does not migrate south for the winter, like elegant trogons. In fact, there are Arizona records for every month.
The high mountain meadows of the Animas Mountains are also the best habitat for the suite of high-elevation hummingbirds for which this area of the country has become famous among birders. Magnificent, white-eared, blue-throated, berylline, calliope, and rufous are the mountain hummingbirds among the 15 species recorded in the region.
The Animas and higher elevations of the Peloncillo Mountains contain the Apache race of the northern goshawk Accipiter gentilis apache. This is the only place with contiguous mountain habitat connecting the Sierra Madre population with those in the U.S. The Peloncillos and Animas are two of the three mountain ranges in the U.S. where Mexican chickadees are found, the other being the nearby Chiricahua Mountains.
Extirpated species
Two species extirpated from the U.S. but still found in Mexico have the potential for recolonization in the Peloncillos region. The aplomado falcon, a beautiful medium-sized falcon once relatively common in the desert grasslands of the Southwest, disappeared around 1910. The habitat at that time was devastated by many years of uncontrolled overgrazing and drought, leading to the desertification of much of the former grassland habitat. Recent research also suggests that the extirpation of prairie dog towns may have had a large hand in the falcon’s decline.7 In recent years the aplomado falcon has been reintroduced into south Texas, and a population in Chihuahua within 100 miles of the U.S. border is well studied. In 2000, an aplomado falcon was observed in southeastern New Mexico, and in 2002 the first nest of these birds seen in New Mexico in many years was observed. The wide- open grassland with scattered yuccas in the periphery of the Peloncillo region would be ideal habitat for aplomado falcons, whether they recolonize naturally or are reintroduced.
The other extirpated species, the thick-billed parrot, was reintroduced to the Chiricahua Mountains in the late 1980s. This short-lived population may have been responsible for the unconfirmed sighting of a thick-billed parrot in the Peloncillo Mountains. This large parrot of the coniferous forests was an irregular visitor to the mountains of southeastern Arizona and southwestern New Mexico in the 1800s. Thick-billed parrots were essentially gone from their former U.S. territory by 1920. Their raucous voices, relatively large size, and tame, inquisitive behavior made them easy targets for subsistence-hunting prospectors and other early settlers. Occasional sightings continued until 1938 in Arizona and until 1964 in New Mexico, but no parrots were recorded thereafter until a few captives were released to the wild in the late 1980s. The reintroduction showed early promise, but it is now believed the birds require a minimum flock size difficult to maintain artificially. Thick-billed parrots are CITES Appendix 1 listed and have become endangered in their remaining Mexican strongholds, principally because of extensive lumbering of old-growth pine forests. As these forests dwindle, it is possible that a flock of these strong fliers might strike out northward from their Chihuahuan home to the Animas Mountain pine forests. The origin of a single thick-billed parrot seen near Truth or Consequences, New Mexico, in the summer of 2003 is still a matter of debate among ornithologists.
Knowledge Gaps
Although a few canyons of the Peloncillo region are well known, other areas are relatively little studied. As stated in the introduction to this chapter, one of the challenges of bird conservation in the region is that much of the knowledge, while valuable, is natural history and anecdotal evidence provided by recreational birdwatchers. What place-based scientific knowledge exists needs to be catalogued. Much of the information presented here on avian diversity was gleaned from two Christmas Count Circles and the Breeding Bird Survey as well as experiences of birders in or near the study area. For example, numerous anecdotal records substantiate the importance of the Peloncillos as a migration corridor. Ongoing monitoring of migrant birds at the Bioresearch Ranch has already yielded four years of detailed data on flyways through the central Peloncillo range, but more systematic monitoring during these critical times needs to be done throughout the region.
Some of the questions posed by these knowledge gaps include: What is the extent to which the habitats of the Peloncillo region are important to neotropical migrants? It is generally understood that the Janos Prairie and Animas Valley are particularly important to wintering species, but what about summer importance? Again, research on the Bioresearch Ranch and Gray Ranch have begun to gather data that address this question, but comprehensive answers will require more concerted efforts to gather and compile information.
How do the grassland bird assemblages compare to grasslands in other regions? Are they declining, and if so, what are the probable causes? The intact riparian habitats of Guadalupe Canyon and Cajon Bonito host some of the rarest species of birds, particularly tropical species (including very high numbers of hummingbirds). Are these species rare due to loss of habitat or to geographic placement at the northern fringe of their ranges?
What is the relationship between fire suppression and loss or decline of such species as thick-billed parrot, Apache goshawk, and other raptors?
The region is well-known by birdwatchers for its high numbers of cavity-nesting species—including woodpeckers and owls—but what are the reasons for this high diversity compared to other Sky Islands?
The avian populations of the northern portion of the region, north of I-10, is even less well-studied than the southern portion, and is only rarely, if ever, visited by birdwatchers. Even in the southern portions, with the exception of a few well-known birding locations (Guadalupe, Clanton and Skeleton Canyons), the remote location and lack of easy access to some public lands have resulted in the Peloncillos being one of the biologically least- known of the Sky Island mountains.
Conservation Targets
The remote location and rugged nature of the Peloncillo region have spared it from many of the development pressures facing most of the other Sky Island mountain ranges. Even the Chiricahua Mountains, the largest of the Arizona Sky Islands, are feeling the encroachment of subdivisions. The Chiricahua Mountains have also hosted several controversies surrounding intensive recreation pressures related to birdwatching. The Peloncillo Mountains have experienced similar controversy; when rare bird reports drew large numbers of birdwatchers (many of whom flew thousands of miles just to see one bird), local ranchers began closing their lands to recreational birdwatching because of the habitat degradation they felt was being caused by vehicular and foot traffic.
Clearly the region as an intact and unbroken landscape is important to birds migrating to the U.S. and Canada from southern Mexico and Central and South America (neotropical migrants), and to more regional migrants. This is evidenced in the large numbers of wintering species, including waterfowl and hawks, which depend on the Janos Prairie and playas of the Animas and northern San Simon Valley. The decline and disappearance in the U.S. of the aplomado falcon points to the need for more understanding this raptor’s conservation needs, as well as the needs of all raptors in the region. Protecting these areas from development or further fragmentation is critical.
More study is also needed to determine the habitat needs of species such as Gould’s turkey, especially related to the return of more natural fire regimes. The same is true for thick-billed parrots if we are to see their return to former haunts in the Chiricahua Mountains. The presence of breeding flocks of thick-billed parrots in the Sierra Cebadillas near the Janos Prairie in Mexico is promising for a potential natural recolonization—as are periodic records of flocks in the Sierra San Luis itself.
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Section Authors:
BIRDS - Thomas Wood. Ornithologist, Southeast Arizona Bird Observatory. Tom is cofounder of the Southeastern Arizona Bird Observatory, a nonprofit conservation organization.